Adrenaline-forming enzyme in brainstem: elevation in genetic and experimental hypertension.

The adrenaline-forming enzyme (phenylethanolamine N-methyltransferase) was elevated in the A1 and A2 regions of the brainstem of 4-week-old spontaneously (genetic) hypertensive rats and in the A1 region of adult experimentally (deoxycorticosterone acetate and sodium chloride) hypertensive rats. The administration of a phenylethanolamine N-methyltransferase inhibitor to experimentally hypertensive animals caused a reduction of the elevated blood pressure to normal values. These results implicate adrenaline-containing neurons in the brainstem in the development of hypertension.